Treesearch

Compares the 1978 National Fire-Danger Rating System and its 20 fuel models, along with other danger rating systems, with observed fire behavior and rates the strengths and weaknesses of models and systems.

Nitrogen and phosphorus flow in litterfall and throughfall were studied in two California Quercus species (the evergreen Q.agrifolia and deciduous Q. lobata) before, during, and after an outbreak of the California oak moth, Phryganidia californica. All of the foliage of both oak species was removed by the herbivore during the course of the outbreak.

Red pine produced significantly more volume than the other species on all five sites in the Lake States. By age 40 to 50 white spruce was second to red pine and beyond this age it is expected that these two species will increase their lead over the other especies even more.

Forest managers face a wide array of potential choices when they consider all of the products derived from woodlands. Many of these products compete with one another to some degree. For instance, hardwood regeneration may be removed in thinnings to favor softwood growth. Forest wildlife-is also influenced by silvicultural practice and the manager must decide whether to encourage only a few species of wildlife or try to manage for the entire wildlife community. If a variety of wildlife is more important, management should attempt to create as much plant diversity as possible. A diversity of...

Because of greater emphasis on nontimber values in New England, uneven-age management is drawing more interest among the larger ownerships. Uneven-age management approaches recommended in the past were both costly and biologically undesirable. However, recent findings are enabling the development of more feasible uneven-age guidelines for regenerating valuable species, conducting practical cutting operations, controlling marking, and keeping records.

This guide explains how to test the condition of living trees or wood products by use of the Shigometer and gives instructions for its use. The guide is in three parts: (1) An introduction on operating principles and applications, (2) an example of the procedure, and (3) a photo guide that gives details on the procedure and background information needed to use it.

The Coleoptera, or beetles, are represented in the world by about 220,000 described species, of which about 24,000 occur in the United States and Canada. A comprehensive taxonomic catalog of beetles for this area has not been available except the series of world-based "Coleopterorum Catalogus" volumes (1909-present, Junk, Berlin). The Leng "Catalogue of the Coleoptera of America North of Mexico" (J. D. Sherman, Jr., Mt. Vernon, NY), which was published in 1920 with supplements to the end of 1947, is a checklist. However, it has served professional and amateur alike for nearly 60 years as...

A general description of Curculio larvae is given. Ke y characters are presented to separate 15 of the 16 described species of eastern North America. A brief key for separating Curculio larvae from Conotrachelus and lepidopterous larvae is presented.

Trees have a spectacular survival record. Over a period of more than 400 million years they have evolved as the tallest, most massive and longest-lived organisms ever to inhabit the earth. Yet trees lack a means of defense that almost every animal has: trees cannot move away from destructive forces. Because they cannot move, all types of living and nonliving enemies—fire, storms, microorganisms, insects, other animals and later man—have wounded them throughout their history. Trees have survived because their evolution has made them into highly compartmented organisms; that is, they wall...

In recent years, there has been increased awareness in maintaining the quality of the environment. This has led to the development and use of microbial agents as alternatives to chemicals for controlling noxious insect populations. The insect pathogens in the family Baculoviridae, by virtue of their specificity, virulence, and safety for nontarget species, have become logical candidates in this regard, and several have been registered with the United States Environmental Protection Agency (EPA) for use in the United States (Martignoni, 1978; Lewis et al., 1979; Ignoffo and Couch, 1981). In...